Conversion process

ABSTRACT

The invention relates to a conversion process for making olefin(s) using a molecular sieve catalyst composition. More specifically, the invention is directed to a process for converting a feedstock comprising an oxygenate in the presence of a molecular sieve catalyst composition, wherein the feedstock is free of or substantially free of metal salts.

This application is a divisional of U.S. patent application No.10/462,256, filed Jun. 16, 2003, now U.S. Pat. No. 7,247,764 which is acontinuation-in-part of U.S. patent application Ser. No. 10/218,728,filed Aug. 14, 2002, now U.S. Pat. No. 7,238,846 which is fullyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a conversion process for makingolefin(s) using a molecular sieve catalyst composition in the presenceof a hydrocarbon feedstock.

BACKGROUND OF THE INVENTION

Olefins are traditionally produced from petroleum feedstock by catalyticor steam cracking processes. These cracking processes, especially steamcracking, produce light olefin(s) such as ethylene and/or propylene forma variety of hydrocarbon feedstocks. Ethylene and propylene areimportant commodity petrochemicals useful in a variety of processes formaking plastics and other chemical compounds.

The petrochemical industry has known for some time that oxygenates,especially alcohols, are convertible into light olefin(s). There arenumerous technologies available for producing oxygenates includingfermentation or reaction of synthesis gas derived from natural gas,petroleum liquids, carbonaceous materials including coal, recycledplastics, municipal waste or any other organic material. Generally, theproduction of synthesis gas involves a combustion, partial oxidation orreforming reaction of natural gas, mostly methane, and an oxygen sourceinto hydrogen, carbon monoxide and/or carbon dioxide. Syngas productionprocesses are well known, and include conventional steam/methanereforming, autothermal reforming, partial oxidation or a combinationthereof.

Methanol, the preferred alcohol for light olefin production, istypically synthesized from the catalytic reaction of hydrogen, carbonmonoxide and/or carbon dioxide in a methanol reactor in the presence ofa heterogeneous catalyst. For example, in one synthesis process methanolis produced using a copper/zinc oxide catalyst in a water-cooled tubularmethanol reactor. The preferred methanol conversion process is generallyreferred to as a methanol-to-olefin(s) process, where methanol isconverted to primarily ethylene and/or propylene in the presence of amolecular sieve.

Methanol conversion processes into one or more olefin(s) typically takesplace in the presence of a molecular sieve. Molecular sieves are poroussolids having pores of different sizes such as zeolites or zeolite-typemolecular sieves, carbons and oxides. The most commercially usefulmolecular sieves for the petroleum and petrochemical industries areknown as zeolites, for example aluminosilicate molecular sieves.Molecular sieves in general have a one-, two- or three-dimensionalcrystalline pore structure having uniformly sized pores of moleculardimensions that selectively adsorb molecules that can enter the pores,and exclude those molecules that are too large.

There are many different types of molecular sieves well known to converta feedstock, especially an oxygenate containing feedstock, into one ormore olefin(s). For example, U.S. Pat. No. 5,367,100 describes the useof a well known zeolite, ZSM-5, to convert methanol into olefin(s); U.S.Pat. No. 4,062,905 discusses the conversion of methanol and otheroxygenates to ethylene and propylene using crystalline aluminosilicatezeolites, for example Zeolite T, ZK5, erionite and chabazite; U.S. Pat.No. 4,079,095 describes the use of ZSM-34 to convert methanol tohydrocarbon products such as ethylene and propylene; U.S. Pat. No.4,310,440 describes producing light olefin(s) from an alcohol using acrystalline aluminophosphates, often represented by ALPO₄; and one ofthe most useful molecular sieves for converting methanol to olefin(s) isa silicoaluminophosphate molecular sieves. Silicoaluminophosphate (SAPO)molecular sieves contain a three-dimensional microporous crystallineframework structure of [SiO₂], [AlO₂] and [PO₂] corner sharingtetrahedral units and is useful in converting a hydrocarbon feedstockinto olefin(s), particularly where the feedstock is methanol. See forexample, U.S. Pat. Nos. 4,440,871, 4,499,327, 4,677,242, 4,677,243,4,873,390, 5,095,163, 5,714,662 and 6,166,282, all of which are hereinfully incorporated by reference.

These molecular sieves are sensitive to various contaminants resultingin the lowering of their selectivity to produce light olefin(s) andreducing the operability of a conversion process. These contaminants areintroduced to a particular conversion process in a variety of ways.Sometimes the molecular sieve itself results in the generation ofcontaminants affecting the conversion performance of the molecularsieve. In addition, in large scale processes it is more likely that theeffect of various contaminants entering into commercial conversionprocesses are higher.

Therefore, it would be highly desirable to control contamination so asnot to adversely affect the molecular sieve catalyst. Controllingcontamination is particularly desirable in oxygenate to olefinreactions, particularly in methanol to olefin reactions, where grade Aand AA feedstocks, which are typically used, are relatively expensive.Such feedstocks also have to be shipped over large distances, often overlarge bodies of water, and are highly susceptible to being contaminatedduring shipping.

SUMMARY OF THE INVENTION

This invention provides for a process for converting a feedstock in thepresence of a molecular sieve into one or more olefin(s), whilecontrolling contamination of the feedstock. Contamination of thefeedstock can be controlled by providing a feedstock having anappropriate conductivity level. The conductivity level can accuratelyreflect contamination levels, particularly metals contamination levels,more particularly metal salt contamination, which can have an especiallynegative impact on molecular sieve catalysts.

In one embodiment, the invention is directed to a process for convertinggreater than 1000 Kg per hour of a feedstock in the presence of amolecular sieve into one or more olefin(s), wherein the feedstock havinga conductivity of not greater than about 10 uS/cm, preferably notgreater than about 5 uS/cm, more preferably not greater than about 3uS/cm, and most preferably not greater than about 2 uS/cm. In anotherembodiment, the feedstock comprises seawater. In yet another embodiment,the feedstock comprises not greater than about 50 ppm, preferably notgreater than about 30 ppm, more preferably not greater than about 20ppm, and most preferably not greater than about 10 ppm of a Group IAmetal salt or a Group IIA metal salt. Preferably the feedstock comprisesan oxygenate such as an alcohol and/or an ether, for example methanoland/or dimethyl ether.

In an embodiment, the invention is directed to a process for convertinga feedstock in the presence of a molecular sieve in a reactor, theprocess comprising the steps of: (a) introducing to the reactor afeedstock at a rate of 1,000 Kg of feedstock per hour, preferablygreater than 10,000 Kg per hour, wherein the feedstock has aconductivity of not greater than about 10 uS/cm; (b) introducing amolecular sieve to the reactor; and (c) withdrawing an effluent streamfrom the reactor, the effluent stream comprising greater than 1,000 Kgof one or more olefin(s) per hour. Preferably, the feedstock furthercomprises an oxygenate such as methanol and/or dimethyl ether and theolefin(s) are ethylene and/or propylene. In a preferred embodiment, thefeedstock comprises methanol and a Group IA metal salt, in particularsodium or potassium chloride, and the molecular sieve is asilicoaluminophosphate or aluminophosphate, or a mixture thereof.

In another embodiment, the invention is directed to a process forconverting a feedstock in the presence of a molecular sieve or catalystcomposition thereof in a reactor to produce greater than 1,000 Kg perhour of one or more olefin(s), the process operating with a feedstockhaving a conductivity less than 2 uS/cm. Preferably greater than 2,000Kg per hour of ethylene and/or propylene, and more preferably greaterthan 4,000 Kg per hour of ethylene and propylene. In this embodiment,the rate of feedstock entering the reactor per day is greater than100,000 Kg per day.

In yet another embodiment, the invention relates to a process forconverting a feedstock, preferably a feedstock comprising an oxygenate,the process comprising the steps of (a) providing a feedstock having arelatively high conductivity such as for example greater than 10 uS/cm;(b) reducing the conductivity of the feedstock to not greater than about10 uS/cm; preferably not greater than about 5 uS/cm; still preferablynot greater than about 3 uS/cm, more preferably not greater than about 2uS/cm to form a treated feedstock; (c) introducing the treated feedstockinto a reactor; (d) providing a molecular sieve catalyst composition inthe reactor to convert the treated feedstock into one or more olefin(s);and (e) withdrawing an effluent stream comprising the one or moreolefin(s) from the reactor. In a preferred embodiment, the feedstockcomprises methanol and seawater.

In another embodiment of all the embodiments described above, themolecular sieve is synthesized from a combination of at least two,preferably at least three, of the group consisting of a silicon source,a phosphorous source and an aluminum source, optionally in the presenceof a templating agent. In the most preferred embodiment, the molecularsieve is a silicoaluminophosphate or aluminophosphate, most preferably asilicoaluminophosphate.

In yet another embodiment, there is provided a process for convertingoxygenate to olefin, which comprises providing an oxygenate compositionhaving a positive conductivity of not greater than 10 uS/cm andcontaining at least one Group IA or Group IIA metal salt. The oxygenatecomposition is contacted with a molecular sieve to convert oxygenate inthe oxygenate composition to olefin. Preferably, the conductivity of theprovided oxygenate composition is at least 1.5 uS/cm.

In another embodiment, the process for converting oxygenate to olefincomprises providing an oxygenate composition containing at least oneGroup IA or Group IIA metal salt. Preferably, the provided oxygenatecomposition has a conductivity of not greater than 750 uS/cm, morepreferably, a conductivity of not greater than 500 uS/cm, and mostpreferably a conductivity of not greater than 300 uS/cm. Theconductivity of the oxygenate composition is reduced to not greater than10 uS/cm to form a treated feedstock, and the treated feedstock iscontacted with a molecular sieve to convert oxygenate in the oxygenatecomposition to olefin.

DETAILED DESCRIPTION OF THE INVENTION

I. Introduction

The invention is directed toward a conversion process of a hydrocarbonfeedstock, particularly methanol, in the presence of molecular sievecatalyst composition to one or more olefin(s). In this invention, thefeedstock is low in contaminants so as not to significantly have anadverse effect on catalyst life or selectivity to desired product.Although the presence of only trace amounts of various contaminants inthe feedstock can severely impact the life or selectivity of themolecular sieve catalyst, this invention allows the presence of certaincontaminants in the feedstock at low levels. In fact, according tocertain preferred embodiments of this invention, the presence of certainmetal salts, particularly sodium metal salts, especially sodiumchloride, at low concentrations in the feed can actually have a positiveeffect on selectivity to desired olefin product such as ethylene andpropylene.

In one embodiment of the invention, desired or tolerable levels ofcontaminants in the hydrocarbon feedstock of this invention aredetermined by the conductivity of the feedstock. The feedstockpreferably exhibits a positive conductivity to a level that does notsignificantly reduce selectivity to desired olefin product. Inparticular,.the positive conductivity of the feedstock is at a level inwhich the selectivity to ethylene and propylene product is notsignificantly reduced compared to that of a feedstock having asubstantially neutral conductivity. In making conductivitydeterminations, it is preferable in this invention to use a SchottGeräte Conductivity Measurement Cell (Type CG857; Cell LF100) in thetemperature range of from about 7° C. to about 50° C.

In this invention, it is desired that the feedstock have a positiveconductivity of not greater than about 10 uS/cm. Preferably, thefeedstock has a positive conductivity of not greater than about 5 uS/cm,more preferably not greater than about 3 uS/cm, and most preferably notgreater than about 2 uS/cm. According to this invention, positiveconductivity means greater than 0 uS/cm. Preferably, the feedstock has apositive conductivity of at least about 1.5 uS/cm.

In another embodiment of the invention, the feedstock contains seawateror metals contained in the feedstock as a result of the feedstock havingcontacted seawater. The presence of such metals does not have to bedirectly determined, however. It is sufficient to determine theconductivity of the feedstock to assess the level of contamination. Theamount of contaminants present in the feedstock is directly correlatablein this invention to the desired conductivity limits.

In yet another embodiment of the invention, the feedstock contains atleast one Group IA or IIA metal salt. Preferred Group IA metal saltsinclude lithium, sodium, and potassium salts. Halide salts of Group IAmetals, particularly lithium, sodium, and potassium, are particularlypreferred. Particularly desired are chloride salts of lithium, sodium,and potassium. Preferred Group IIA metal salts include magnesium andcalcium salts. Halide salts of Group IIA metals, particularly magnesiumand calcium, are particularly preferred. The limited presence of sodiumchloride is most preferred. Such salts can actually contribute toenhancing, or at least not affecting, selectivity to ethylene andpropylene product.

According to this invention, some reduction in catalyst life isacceptable as a result of feedstock containing contaminants,particularly seawater contaminants, more particularly the Group IAand/or Group IIA metal contaminants. Generally, it is preferred thatcatalyst life be reduced by an amount of not greater than 20% relativeto that of a feedstock having a substantially neutral conductivity.Preferably, catalyst life is reduced by an amount of not greater than15%, more preferably not greater than 10% relative to that of afeedstock having a substantially neutral conductivity.

In embodiments of the invention in which the feedstock containsseawater, the seawater should be at concentrations in which theconductivity remains within desirable ranges. In one embodiment, theseawater concentration of the feedstock is not greater than 250 wppm,based on total weight of the feedstock. Preferably, the seawaterconcentration is not greater than 200 wppm, more preferably not greaterthan 150 wppm, and most preferably not greater than 100 wppm, based ontotal weight of the feedstock.

II. Molecular Sieves and Catalysts Thereof

Molecular sieves have various chemical and physical, framework,characteristics. Molecular sieves have been well classified by theStructure Commission of the International Zeolite Association accordingto the rules of the IUPAC Commission on Zeolite Nomenclature. Aframework-type describes the connectivity, topology, of thetetrahedrally coordinated atoms constituting the framework, and makingan abstraction of the specific properties for those materials.Framework-type zeolite and zeolite-type molecular sieves for which astructure has been established, are assigned a three letter code and aredescribed in the Atlas of Zeolite Framework Types, 5th edition,Elsevier, London, England (2001), which is herein fully incorporated byreference.

Non-limiting examples of these molecular sieves are the small poremolecular sieves, AEI, AFT, APC, ATN, ATT, ATV, AWW, BIK, CAS, CHA, CHI,DAC, DDR, EDI, ERI, GOO, KFI, LEV, LOV, LTA, MON, PAU, PHI, RHO, ROG,THO, and substituted forms thereof; the medium pore molecular sieves,AFO, AEL, EUO, HEU, FER, MEL, MFI, MTW, MTT, TON, and substituted formsthereof; and the large pore molecular sieves, EMT, FAU, and substitutedforms thereof. Other molecular sieves include ANA, BEA, CFI, CLO, DON,GIS, LTL, MER, MOR, MWW and SOD. Non-limiting examples of the preferredmolecular sieves, particularly for converting an oxygenate containingfeedstock into olefin(s), include AEI, AEL, AFY, BEA, CHA, EDI, FAU,FER, GIS, LTA, LTL, MER, MFI, MOR, MTT, MWW, TAM and TON. In onepreferred embodiment, the molecular sieve of the invention has an AEItopology or a CHA topology, or a combination thereof, most preferably aCHA topology.

Molecular sieve materials all have 3-dimensional framework structure ofcorner-sharing TO₄ tetrahedra, where T is any tetrahedrally coordinatedcation. These molecular sieves are typically described in terms of thesize of the ring that defines a pore, where the size is based on thenumber of T atoms in the ring. Other framework-type characteristicsinclude the arrangement of rings that form a cage, and when present, thedimension of channels, and the spaces between the cages. See van Bekkum,et al., Introduction to Zeolite Science and Practice, Second CompletelyRevised and Expanded Edition, Volume 137, pages 1-67, Elsevier Science,B.V., Amsterdam, Netherlands (2001).

The small, medium and large pore molecular sieves have from a 4-ring toa 12-ring or greater framework-type. In a preferred embodiment, thezeolitic molecular sieves have 8-, 10- or 12-ring structures or largerand an average pore size in the range of from about 3 Å to 15 Å. In themost preferred embodiment, the molecular sieves of the invention,preferably silicoaluminophosphate molecular sieves have 8-rings and anaverage pore size less than about 5 Å, preferably in the range of from 3Å to about 5 Å, more preferably from 3 Å to about 4.5 Å, and mostpreferably from 3.5 Å to about 4.2 Å.

Molecular sieves, particularly zeolitic and zeolitic-type molecularsieves, preferably have a molecular framework of one, preferably two ormore corner-sharing [TO₄] tetrahedral units, more preferably, two ormore [SiO₄], [AlO₄] and/or [PO₄] tetrahedral units, and most preferably[SiO₄], [AlO₄] and [PO₄] tetrahedral units. These silicon, aluminum, andphosphorous based molecular sieves and metal containing silicon,aluminum and phosphorous based molecular sieves have been described indetail in numerous publications including for example, U.S. Pat. No.4,567,029 (MeAPO where Me is Mg, Mn, Zn, or Co), U.S. Pat. No. 4,440,871(SAPO), European Patent Application EP-A-0 159 624 (ELAPSO where El isAs, Be, B, Cr, Co, Ga, Ge, Fe, Li, Mg, Mn, Ti or Zn), U.S. Pat. No.4,554,143 (FeAPO), U.S. Patents No. 4,822,478, 4,683,217, 4,744,885(FeAPSO), EP-A-0 158 975 and U.S. Pat. No. 4,935,216 (ZnAPSO, EP-A-0 161489 (CoAPSO), EP-A-0 158 976 (ELAPO, where EL is Co, Fe, Mg, Mn, Ti orZn), U.S. Pat. No. 4,310,440 (AIPO₄), EP-A-0 158 350 (SENAPSO), U.S.Pat. No. 4,973,460 (LiAPSO), U.S. Pat. No. 4,789,535 (LiAPO), U.S. Pat.No. 4,992,250 (GeAPSO), U.S. Pat. No. 4,888,167 (GeAPO), U.S. Pat. No.5,057,295 (BAPSO), U.S. Pat. No. 4,738,837 (CrAPSO), U.S. Patents Nos.4,759,919, and 4,851,106 (CrAPO), U.S. Pat. Nos. 4,758,419, 4,882,038,5,434,326 and 5,478,787 (MgAPSO), U.S. Pat. No. 4,554,143 (FeAPO), U.S.Pat. No. 4,894,213 (AsAPSO), U.S. Pat. No. 4,913,888 (AsAPO), U.S. Pat.Nos. 4,686,092, 4,846,956 and 4,793,833 (MnAPSO), U.S. Pat. Nos.5,345,011 and 6,156,931 (MnAPO), U.S. Pat. No. 4,737,353 (BeAPSO), U.S.Pat. No. 4,940,570 (BeAPO), U.S. Pat. Nos. 4,801,309, 4,684,617 and4,880,520 (TiAPSO), U.S. Pat. Nos. 4,500,651, 4,551,236 and 4,605,492(TiAPO), U.S. Pat. No. 4,824,554, 4,744,970 (CoAPSO), U.S. Pat. No.4,735,806 (GaAPSO) EP-A-0 293 937 (QAPSO, where Q is framework oxideunit [QO₂]), as well as U.S. Pat. Nos. 4,567,029, 4,686,093, 4,781,814,4,793,984, 4,801,364, 4,853,197, 4,917,876, 4,952,384, 4,956,164,4,956,165, 4,973,785, 5,241,093, 5,493,066 and 5,675,050, all of whichare herein fully incorporated by reference. Other molecular sieves aredescribed in R. Szostak, Handbook of Molecular Sieves, Van NostrandReinhold, New York, N.Y. (1992), which is herein fully incorporated byreference.

The more preferred silicon, aluminum and/or phosphorous containingmolecular sieves, and aluminum, phosphorous, and optionally silicon,containing molecular sieves include aluminophosphate (ALPO) molecularsieves and silicoaluminophosphate (SAPO) molecular sieves andsubstituted, preferably metal substituted, ALPO and SAPO molecularsieves. The most preferred molecular sieves are SAPO molecular sieves,and metal substituted SAPO molecular sieves. In an embodiment, the metalis an alkali metal of Group IA of the Periodic Table of Elements, analkaline earth metal of Group IIA of the Periodic Table of Elements, arare earth metal of Group IIIB, including the Lanthanides: lanthanum,cerium, praseodymium, neodymium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium;and scandium or yttrium of the Periodic Table of Elements, a transitionmetal of Groups IVB, VB, VIB, VIIB, VIIIB, and IB of the Periodic Tableof Elements, or mixtures of any of these metal species. In one preferredembodiment, the metal is selected from the group consisting of Co, Cr,Cu, Fe, Ga, Ge, Mg, Mn, Ni, Sn, Ti, Zn and Zr, and mixtures thereof. Inanother preferred embodiment, these metal atoms discussed above areinserted into the framework of a molecular sieve through a tetrahedralunit, such as [MeO₂], and carry a net charge depending on the valencestate of the metal substituent. For example, in one embodiment, when themetal substituent has a valence state of +2, +3, +4, +5, or +6, the netcharge of the tetrahedral unit is between −2 and +2.

In one embodiment, the molecular sieve, as described in many of the U.S.Patents mentioned above, is represented by the empirical formula, on ananhydrous basis:mR:(M_(x)Al_(y)P_(z))O₂wherein R represents at least one templating agent, preferably anorganic templating agent; m is the number of moles of R per mole of(M_(x)Al_(y)P_(z))O₂ and m has a value from 0 to 1, preferably 0 to 0.5,and most preferably from 0 to 0.3; x, y, and z represent the molefraction of Al, P and M as tetrahedral oxides, where M is a metalselected from one of Group IA, IIA, IB, IIIB, IVB, VB, VIB, VIIB, VIIIBand Lanthanide's of the Periodic Table of Elements, preferably M isselected from one of the group consisting of Co, Cr, Cu, Fe, Ga, Ge, Mg,Mn, Ni, Sn, Ti, Zn and Zr. In an embodiment, m is greater than or equalto 0.2, and x, y and z are greater than or equal to 0.01. In anotherembodiment, m is greater than 0.1 to about 1, x is greater than 0 toabout 0.25, y is in the range of from 0.4 to 0.5, and z is in the rangeof from 0.25 to 0.5, more preferably m is from 0.15 to 0.7, x is from0.01 to 0.2, y is from 0.4 to 0.5, and z is from 0.3 to 0.5.

Non-limiting examples of SAPO and ALPO molecular sieves of the inventioninclude one or a combination of SAPO-5, SAPO-8, SAPO-11, SAPO-16,SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37,SAPO-40, SAPO-41, SAPO-42, SAPO-44 (U.S. Pat. No. 6,162,415), SAPO-47,SAPO-56, ALPO-5, ALPO-11, ALPO-18, ALPO-31, ALPO-34, ALPO-36, ALPO-37,ALPO-46, and metal containing molecular sieves thereof. The morepreferred zeolite-type molecular sieves include one or a combination ofSAPO-18, SAPO-34, SAPO-35, SAPO-44, SAPO-56, ALPO-18 and ALPO-34, evenmore preferably one or a combination of SAPO-18, SAPO-34, ALPO-34 andALPO-18, and metal containing molecular sieves thereof, and mostpreferably one or a combination of SAPO-34 and ALPO-18, and metalcontaining molecular sieves thereof.

In an embodiment, the molecular sieve is an intergrowth material havingtwo or more distinct phases of crystalline structures within onemolecular sieve composition. In particular, intergrowth molecular sievesare described in the U.S. patent application Ser. No.09/924,016 filedAug. 7, 2001 and PCT WO 98/15496 published Apr. 16, 1998, both of whichare herein fully incorporated by reference. For example, SAPO-18,ALPO-18 and RUW-18 have an AEI framework-type, and SAPO-34 has a CHAframework-type. In another embodiment, the molecular sieve comprises atleast one intergrown phase of AEI and CHA framework-types, preferablythe molecular sieve has a greater amount of CHA framework-type to AEIframework-type, and more preferably the ratio of CHA to AEI is greaterthan 1:1.

III. Molecular Sieve Synthesis

The synthesis of molecular sieves is described in many of the referencesdiscussed above. Generally, molecular sieves are synthesized by thehydrothermal crystallization of one or more of a source of aluminum, asource of phosphorous, a source of silicon, a templating agent, and ametal containing compound. Typically, a combination of sources ofsilicon, aluminum and phosphorous, optionally with one or moretemplating agents and/or one or more metal containing compounds areplaced in a sealed pressure vessel, optionally lined with an inertplastic such as polytetrafluoroethylene, and heated, under acrystallization pressure and temperature, until a crystalline materialis formed, and then recovered by filtration, centrifugation and/ordecanting.

In a preferred embodiment, the molecular sieves are synthesized byforming a reaction product of a source of silicon, a source of aluminum,a source of phosphorous, an organic templating agent, preferably anitrogen containing organic templating agent. This particularlypreferred embodiment results in the synthesis of asilicoaluminophosphate crystalline material that is then isolated byfiltration, centrifugation and/or decanting.

Non-limiting examples of silicon sources include a silicates, flumedsilica, for example, Aerosil-200 available from Degussa Inc., New York,N.Y., and CAB-O-SIL M-5, silicon compounds such as tetraalkylorthosilicates, for example, tetramethyl orthosilicate (TMOS) andtetraethylorthosilicate (TEOS), colloidal silicas or aqueous suspensionsthereof, for example Ludox-HS-40 sol available from E.I. du Pont deNemours, Wilmington, Del., silicic acid, alkali-metal silicate, or anycombination thereof. The preferred source of silicon is a silica sol.

Non-limiting examples of aluminum sources include aluminum-containingcompositions such as aluminum alkoxides, for example aluminumisopropoxide, aluminum phosphate, aluminum hydroxide, sodium aluminate,pseudo-boehmite, gibbsite and aluminum trichloride, or any combinationsthereof. A preferred source of aluminum is pseudo-boehmite, particularlywhen producing a silicoaluminophosphate molecular sieve.

Non-limiting examples of phosphorous sources, which may also includealuminum-containing phosphorous compositions, includephosphorous-containing, inorganic or organic, compositions such asphosphoric acid, organic phosphates such as triethyl phosphate, andcrystalline or amorphous aluminophosphates such as ALPO₄, phosphoroussalts, or combinations thereof. The preferred source of phosphorous isphosphoric acid, particularly when producing a silicoaluminophosphate.

Templating agents are generally compounds that contain elements of GroupVB of the Periodic Table of Elements, particularly nitrogen, phosphorus,arsenic and antimony, more preferably nitrogen or phosphorous, and mostpreferably nitrogen. Typical templating agents of Group VB of thePeriodic Table of elements also contain at least one alkyl or arylgroup, preferably an alkyl or aryl group having from 1 to 10 carbonatoms, and more preferably from 1 to 8 carbon atoms. The preferredtemplating agents are nitrogen-containing compounds such as amines andquaternary ammonium compounds.

The quaternary ammonium compounds, in one embodiment, are represented bythe general formula R₄N+, where each R is hydrogen or a hydrocarbyl orsubstituted hydrocarbyl group, preferably an alkyl group or an arylgroup having from 1 to 10 carbon atoms. In one embodiment, thetemplating agents include a combination of one or more quaternaryammonium compound(s) and one or more of a mono-, di- or tri-amine.

Non-limiting examples of templating agents include tetraalkyl ammoniumcompounds including salts thereof such as tetramethyl ammonium compoundsincluding salts thereof, tetraethyl ammonium compounds including saltsthereof, tetrapropyl ammonium including salts thereof, andtetrabutylammonium including salts thereof, cyclohexylamine, morpholine,di-n-propylamine (DPA), tripropylamine, triethylamine (TEA),triethanolamine, piperidine, cyclohexylamine, 2-methylpyridine,N,N-dimethylbenzylamine, N,N-diethylethanolamine, dicyclohexylamine,N,N-dimethylethanolamine, choline, N,N′-dimethylpiperazine,1,4-diazabicyclo(2,2,2)octane, N′,N′,N,N-tetramethyl-(1,6)hexanediamine,N-methyldiethanolamine, N-methyl-ethanolamine, N-methyl piperidine,3-methyl-piperidine, N-methylcyclohexylamine, 3-methylpyridine,4-methyl-pyridine, quinuclidine,N,N′-dimethyl-1,4-diazabicyclo(2,2,2)octane ion; di-n-butylamine,neopentylamine, di-n-pentylamine, isopropylamine, t-butyl-amine,ethylenediamine, pyrrolidine, and 2-imidazolidone.

The preferred templating agent or template is a tetraethylammoniumcompound, such as tetraethyl ammonium hydroxide (TEAOH), tetraethylammonium phosphate, tetraethyl ammonium fluoride, tetraethyl ammoniumbromide, tetraethyl ammonium chloride and tetraethyl ammonium acetate.The most preferred templating agent is tetraethyl ammonium hydroxide andsalts thereof, particularly when producing a silicoaluminophosphatemolecular sieve. In one embodiment, a combination of two or more of anyof the above templating agents is used in combination with one or moreof a silicon-, aluminum-, and phosphorous-source.

A synthesis mixture containing at a minimum a silicon-, aluminum-,and/or phosphorous-composition, and a templating agent, should have a pHin the range of from 2 to 10, preferably in the range of from 4 to 9,and most preferably in the range of from 5 to 8. Generally, thesynthesis mixture is sealed in a vessel and heated, preferably underautogenous pressure, to a temperature in the range of from about 80° C.to about 250° C., and more preferably from about 150° C. to about 180°C. The time required to form the crystalline product is typically fromimmediately up to several weeks, the duration of which is usuallydependent on the temperature; the higher the temperature the shorter theduration. Typically, the crystalline molecular sieve product is formed,usually in a slurry state, and is recovered by any standard techniquewell known in the art, for example centrifugation or filtration. Theisolated or separated crystalline product, in an embodiment, is washed,typically, using a liquid such as water, from one to many times. Thewashed crystalline product is then optionally dried, preferably in air.

In one preferred embodiment, when a templating agent is used in thesynthesis of a molecular sieve, it is preferred that the templatingagent is substantially, preferably completely, removed aftercrystallization by numerous well known techniques, for example, heattreatments such as calcination. Calcination involves contacting themolecular sieve containing the templating agent with a gas, preferablycontaining oxygen, at any desired concentration at an elevatedtemperature sufficient to either partially or completely decompose andoxidize the templating agent.

Molecular sieves have either a high silicon (Si) to aluminum (Al) ratioor a low silicon to aluminum ratio, however, a low Si/Al ratio ispreferred for SAPO synthesis. In one embodiment, the molecular sieve hasa Si/Al ratio less than 0.65, preferably less than 0.40, more preferablyless than 0.32, and most preferably less than 0.20. In anotherembodiment the molecular sieve has a Si/Al ratio in the range of fromabout 0.65 to about 0.10, preferably from about 0.40 to about 0.10, morepreferably from about 0.32 to about 0.10, and more preferably from about0.32 to about 0.15.

IV. Method For Making Mmolecular Sieve Cataltst Compositions

Once the molecular sieve is synthesized, depending on the requirementsof the particular conversion process, the molecular sieve is thenformulated into a molecular sieve catalyst composition, particularly forcommercial use. The molecular sieves synthesized above are made orformulated into molecular sieve catalyst compositions by combining thesynthesized molecular sieve(s) with a binder and optionally, butpreferably, a matrix material to form a molecular sieve catalystcomposition or a formulated molecular sieve catalyst composition. Thisformulated molecular sieve catalyst composition is formed into usefulshape and sized particles by well-known techniques such as spray drying,pelletizing, extrusion, and the like.

There are many different binders that are useful in forming themolecular sieve catalyst composition. Non-limiting examples of bindersthat are useful alone or in combination include various types ofhydrated alumina, silicas, and/or other inorganic oxide sol. Onepreferred alumina containing sol is aluminum chlorhydrate. The inorganicoxide sol acts like glue binding the synthesized molecular sieves andother materials such as the matrix together, particularly after thermaltreatment. Upon heating, the inorganic oxide sol, preferably having alow viscosity, is converted into an inorganic oxide matrix component.For example, an alumina sol will convert to an aluminum oxide matrixfollowing heat treatment.

Aluminum chlorhydrate, a hydroxylated aluminum based sol containing achloride counter ion, has the general formula ofAl_(m)O_(n)(OH)_(o)Cl_(p).x((H₂O) wherein m is 1 to 20, n is 1 to 8, ois 5 to 40, p is 2 to 15, and x is 0 to 30. In one embodiment, thebinder is Al₁₃O₄(OH)₂₄Cl₇.12(H₂O) as is described in G. M. Wolterman, etal., Stud. Surf. Sci. and Catal., 76, pages 105-144 (1993), which isherein incorporated by reference. In another embodiment, one or morebinders are combined with one or more other non-limiting examples ofalumina materials such as aluminum oxyhydroxide, γ-alumina, boehmite,diaspore, and transitional aluminas such as α-alumina, β-alumina,γ-alumina, δ-alumina, ε-alumina, κ-alumina, and ρ-alumina, aluminumtrihydroxide, such as gibbsite, bayerite, nordstrandite, doyelite, andmixtures thereof.

In another embodiment, the binders are alumina sols, predominantlycomprising aluminum oxide, optionally including some silicon. In yetanother embodiment, the binders are peptized alumina made by treatingalumina hydrates such as pseudobohemite, with an acid, preferably anacid that does not contain a halogen, to prepare sols or aluminum ionsolutions. Non-limiting examples of commercially available colloidalalumina sols include Nalco 8676 available from Nalco Chemical Co.,Naperville, Ill., and Nyacol AL200DW available from Nyacol NanoTechnologies, Inc., Ashland, Mass.

The molecular sieve described above, in a preferred embodiment, iscombined with one or more matrix material(s). Matrix materials aretypically effective in reducing overall catalyst cost, act as thermalsinks assisting in shielding heat from the catalyst composition forexample during regeneration, densifying the catalyst composition,increasing catalyst strength such as crush strength and attritionresistance, and to control the rate of conversion in a particularprocess.

Non-limiting examples of matrix materials include one or more of: rareearth metals, non-active, metal oxides including titania, zirconia,magnesia, thoria, beryllia, quartz, silica or sols, and mixturesthereof, for example silica-magnesia, silica-zirconia, silica-titania,silica-alumina and silica-alumina-thoria.

In an embodiment, matrix materials are natural clays such as those fromthe families of montmorillonite and kaolin. These natural clays includesabbentonites and those kaolins known as, for example, Dixie, McNamee,Georgia and Florida clays. Non-limiting examples of other matrixmaterials include: haloysite, kaolinite, dickite, nacrite, or anauxite.In one embodiment, the matrix material, preferably any of the clays, aresubjected to well known modification processes such as calcinationand/or acid treatment and/or chemical treatment.

In one preferred embodiment, the matrix material is a clay or aclay-type composition, preferably the clay or clay-type compositionhaving a low iron or titania content, and most preferably the matrixmaterial is kaolin. Kaolin has been found to form a pumpable, high solidcontent slurry, it has a low fresh surface area, and it packs togethereasily due to its platelet structure. A preferred average particle sizeof the matrix material, most preferably kaolin, is from about 0.1 μm toabout 0.6 μm with a D₉₀ particle size distribution of less than about 1μm.

Upon combining the molecular sieve, the binder, and optionally thematrix material, in a liquid to form a slurry, mixing, preferablyrigorous mixing is needed to produce a substantially homogeneousmixture. Non-limiting examples of suitable liquids include one or acombination of water, alcohol, ketones, aldehydes, and/or esters. Themost preferred liquid is water. In one embodiment, the slurry iscolloid-milled for a period of time sufficient to produce the desiredslurry texture, sub-particle size, and/or sub-particle sizedistribution.

The molecular sieve, the binder, and the matrix material, are in thesame or different liquid, and are combined in any order, together,simultaneously, sequentially, or a combination thereof. In the preferredembodiment, the same liquid, preferably water is used. The molecularsieve, matrix material, and the binder, are combined in a liquid assolids, substantially dry or in a dried form, or as slurries, togetheror separately. If solids are added together as dry or substantiallydried solids, it is preferable to add a limited and/or controlled amountof liquid.

In one embodiment, the slurry of the molecular sieve, the binder and thematrix materials is mixed or milled to achieve a sufficiently uniformslurry of sub-particles of the molecular sieve catalyst composition thatis then fed to a forming unit that produces the molecular sieve catalystcomposition. In a preferred embodiment, the forming unit is a spraydryer. Typically, the forming unit is maintained at a temperaturesufficient to remove most of the liquid from the slurry, and from theresulting molecular sieve catalyst composition. The resulting catalystcomposition when formed in this way takes the form of microspheres.

When a spray dryer is used as the forming unit, typically, the slurry ofthe molecular sieve, the binder and the matrix material is co-fed to thespray drying volume with a drying gas with an average inlet temperatureranging from 100° C. to 550° C., and a combined outlet temperatureranging from 50° C. to about 225° C. In an embodiment, the averagediameter of the spray dried formed catalyst composition is from about 10μm to about 300 μm, preferably from about 15 μm to about 250 μm, morepreferably from about 18 μm to about 200 μm, and most preferably fromabout 20 μm to about 120 μm.

During spray drying, the slurry is passed through a nozzle distributingthe slurry into small droplets, resembling an aerosol spray into adrying chamber. Atomization is achieved by forcing the slurry through asingle nozzle or multiple nozzles with a pressure drop in the range offrom 100 psia to 1000 psia (690 kpaa to 6895 kpaa). In anotherembodiment, the slurry is co-fed through a single nozzle or multiplenozzles along with an atomization fluid such as air, steam, flue gas, orany other suitable gas.

In yet another embodiment, the slurry described above is directed to theperimeter of a spinning wheel that distributes the slurry into smalldroplets, the size of which is controlled by many factors includingslurry viscosity, surface tension, flow rate, pressure, and temperatureof the slurry, the shape and dimension of the nozzle(s), or the spinningrate of the wheel. These droplets are then dried in a co-current orcounter-current flow of air passing through a spray drier to form asubstantially dried or dried molecular sieve catalyst composition, morespecifically a molecular sieve catalyst composition in powder form.

Generally, the size of the powder is controlled to some extent by thesolids content of the slurry. However, control of the size of thecatalyst composition and its spherical characteristics are controllableby varying the slurry feed properties and conditions of atomization.

Other methods for forming a molecular sieve catalyst composition isdescribed in U.S. patent application Ser. No. 09/617,714 filed Jul. 17,2000 (spray drying using a recycled molecular sieve catalystcomposition), which is herein incorporated by reference.

In another embodiment, the formulated molecular sieve catalystcomposition contains from about 1% to about 99%, preferably from about10% to about 90%, more preferably from about 10% to about 80%, even morepreferably from about 20% to about 70%, and most preferably from about25% to about 60% by weight of the molecular sieve based on the totalweight of the molecular sieve catalyst composition.

Once the molecular sieve catalyst composition is formed in asubstantially dry or dried state, to further harden and/or activate theformed catalyst composition, a heat treatment such as calcination, at anelevated temperature is usually performed. A conventional calcinationenvironment is air that typically includes a small amount of watervapor. Typical calcination temperatures are in the range from about 400°C. to about 1,000° C., preferably from about 500° C. to about 800° C.,and most preferably from about 550° C. to about 700° C., preferably in acalcination environment such as air, nitrogen, helium, flue gas(combustion product lean in oxygen), or any combination thereof. In oneembodiment, calcination of the formulated molecular sieve catalystcomposition is carried out in any number of well known devices includingrotary calciners, fluid bed calciners, batch ovens, and the like.Calcination time is typically dependent on the degree of hardening ofthe molecular sieve catalyst composition and the temperature ranges fromabout 15 minutes to about 20 hours, preferably 1 hour to about 2 hours.In a preferred embodiment, the molecular sieve catalyst composition isheated in nitrogen at a temperature of from about 600° C. to about 700°C. Heating is carried out for a period of time typically from 30 minutesto 15 hours, preferably from 1 hour to about 10 hours, more preferably.from about 1 hour to about 5 hours, and most preferably from about 2hours to about 4 hours.

In one embodiment, the attrition resistance of a molecular sievecatalyst composition is measured using an Attrition Rate Index (ARI),measured in weight percent catalyst composition attrited per hour. ARIis measured by adding 6.0 g of catalyst composition having a particlessize ranging from 53 microns to 125 microns to a hardened steelattrition cup. Approximately 23,700 cc/min of nitrogen gas is bubbledthrough a water-containing bubbler to humidify the nitrogen. The wetnitrogen passes through the attrition cup, and exits the attritionapparatus through a porous fiber thimble. The flowing nitrogen removesthe finer particles, with the larger particles being retained in thecup. The porous fiber thimble separates the fine catalyst particles fromthe nitrogen that exits through the thimble. The fine particlesremaining in the thimble represent the catalyst composition that hasbroken apart through attrition. The nitrogen flow passing through theattrition cup is maintained for 1 hour. The fines collected in thethimble are removed from the unit. A new thimble is then installed. Thecatalyst left in the attrition unit is attrited for an additional 3hours, under the same gas flow and moisture levels. The fines collectedin the thimble are recovered. The collection of fine catalyst particlesseparated by the thimble after the first hour are weighed. The amount ingrams of fine particles divided by the original amount of catalystcharged to the attrition cup expressed on per hour basis is the ARI, inweight percent per hour (wt. %/hr). ARI is represented by the formula:ARI=C/(B+C)/D multiplied by 100%, wherein B is weight of catalystcomposition left in the cup after the attrition test, C is the weight ofcollected fine catalyst particles after the first hour of attritiontreatment, and D is the duration of treatment in hours after the firsthour attrition treatment.

In one embodiment, the molecular sieve catalyst composition orformulated molecular sieve catalyst composition has an ARI less than 15weight percent per hour, preferably less than 10 weight percent perhour, more preferably less than 5 weight percent per hour, and even morepreferably less than 2 weight percent per hour, and most preferably lessthan 1 weight percent per hour. In one embodiment, the molecular sievecatalyst composition or formulated molecular sieve catalyst compositionhas an ARI in the range of from 0.1 weight percent per hour to less than5 weight percent per hour, more preferably from about 0.2 weight percentper hour to less than 3 weight percent per hour, and most preferablyfrom about 0.2 weight percent per hour to less than 2 weight percent perhour.

V. Process For Using The Molecular Sieve Catalyst Compositions

The molecular sieve catalyst compositions described above are useful ina variety of processes including: cracking, of for example a naphthafeed to light olefin(s) (U.S. Pat. No. 6,300,537) or higher molecularweight (MW) hydrocarbons to lower MW hydrocarbons; hydrocracking, of forexample heavy petroleum and/or cyclic feedstock; isomerization, of forexample aromatics such as xylene, polymerization, of for example one ormore olefin(s) to produce a polymer product; reforming; hydrogenation;dehydrogenation; dewaxing, of for example hydrocarbons to removestraight chain paraffins; absorption, of for example alkyl aromaticcompounds for separating out isomers thereof; alkylation, of for examplearomatic hydrocarbons such as benzene and alkyl benzene, optionally withpropylene to produce cumeme or with long chain olefins; transalkylation,of for example a combination of aromatic and polyalkylaromatichydrocarbons; dealkylation; hydrodecylization; disproportionation, offor example toluene to make benzene and paraxylene; oligomerization, offor example straight and branched chain olefin(s); anddehydrocyclization.

Preferred processes are conversion processes including: naphtha tohighly aromatic mixtures; light olefin(s) to gasoline, distillates andlubricants; oxygenates to olefin(s); light paraffins to olefins and/oraromatics; and unsaturated hydrocarbons (ethylene and/or acetylene) toaldehydes for conversion into alcohols, acids and esters. The mostpreferred process of the invention is a process directed to theconversion of a feedstock comprising one or more oxygenates to one ormore olefin(s).

The molecular sieve catalyst compositions described above areparticularly useful in conversion processes of different feedstock.Typically, the feedstock contains one or more aliphatic-containingcompounds that include alcohols, amines, carbonyl compounds for examplealdehydes, ketones and carboxylic acids, ethers, halides, mercaptans,sulfides, and the like, and mixtures thereof. The aliphatic moiety ofthe aliphatic-containing compounds typically contains from 1 to about 50carbon atoms, preferably from 1 to 20 carbon atoms, more preferably from1 to 10 carbon atoms, and most preferably from 1 to 4 carbon atoms.

Non-limiting examples of aliphatic-containing compounds include:alcohols such as methanol and ethanol, alkyl-mercaptans such as methylmercaptan and ethyl mercaptan, alkyl-sulfides such as methyl sulfide,alkyl-amines such as methyl amine, alkyl-ethers such as dimethyl ether,diethyl ether and methylethyl ether, alkyl-halides such as methylchloride and ethyl chloride, alkyl ketones such as dimethyl ketone,forrnaldehydes, and various acids such as acetic acid.

In a preferred embodiment of the process of the invention, the feedstockcontains one or more oxygenates, more specifically, one or more organiccompound(s) containing at least one oxygen atom. In the most preferredembodiment of the process of invention, the oxygenate in the feedstockis one or more alcohol(s), preferably aliphatic alcohol(s) where thealiphatic moiety of the alcohol(s) has from 1 to 20 carbon atoms,preferably from 1 to 10 carbon atoms, and most preferably from 1 to 4carbon atoms. The alcohols useful as feedstock in the process of theinvention include lower straight and branched chain aliphatic alcoholsand their unsaturated counterparts.

Non-limiting examples of oxygenates include methanol, ethanol,n-propanol, isopropanol, methyl ethyl ether, dimethyl ether, diethylether, di-isopropyl ether, formaldehyde, dimethyl carbonate, dimethylketone, acetic acid, and mixtures thereof. In the most preferredembodiment, the feedstock is selected from one or more of methanol,ethanol, dimethyl ether, diethyl ether or a combination thereof, morepreferably methanol and dimethyl ether, and most preferably methanol.

The various feedstocks discussed above, particularly a feedstockcontaining an oxygenate, more particularly a feedstock containing analcohol, is converted primarily into one or more olefin(s). Theolefin(s) or olefin monomer(s) produced from the feedstock typicallyhave from 2 to 30 carbon atoms, preferably 2 to 8 carbon atoms, morepreferably 2 to 6 carbon atoms, still more preferably 2 to 4 carbonsatoms, and most preferably ethylene an/or propylene. Non-limitingexamples of olefin monomer(s) include ethylene, propylene, butene-1,pentene-1,4-methyl-pentene-1, hexene-1, octene-1 and decene-1,preferably ethylene, propylene, butene-1, pentene-1,4-methyl-pentene-1,hexene-1, octene-1 and isomers thereof. Other olefin monomer(s) includeunsaturated monomers, diolefins having 4 to 18 carbon atoms, conjugatedor nonconjugated dienes, polyenes, vinyl monomers and cyclic olefins.

In the most preferred embodiment, the feedstock, preferably of one ormore oxygenates, is converted in the presence of a molecular sievecatalyst composition of the invention into olefin(s) having 2 to 6carbons atoms, preferably 2 to 4 carbon atoms. Most preferably, theolefin(s), alone or combination, are converted from a feedstockcontaining an oxygenate, preferably an alcohol, most preferablymethanol, to the preferred olefin(s) ethylene and/or propylene.

The are many processes used to convert feedstock into olefin(s)including various cracking processes such as steam cracking, thermalregenerative cracking, fluidized bed cracking, fluid catalytic cracking,deep catalytic cracking, and visbreaking. The most preferred process isgenerally referred to as gas-to-olefins (GTO) or alternatively,methanol-to-olefins (MTO). In a MTO process, typically an oxygenatedfeedstock, most preferably a methanol containing feedstock, is convertedin the presence of a molecular sieve catalyst composition thereof intoone or more olefin(s), preferably and predominantly, ethylene and/orpropylene, often referred to as light olefin(s).

In one embodiment of the process for conversion of a feedstock,preferably a feedstock containing one or more oxygenates, the amount ofolefin(s) produced based on the total weight of hydrocarbon produced isgreater than 50 weight percent, preferably greater than 60 weightpercent, more preferably greater, than 70 weight percent, and mostpreferably greater than 75 weight percent. In another embodiment of theprocess for conversion of one or more oxygenates to one or moreolefin(s), the amount of ethylene and/or propylene produced based on thetotal weight of hydrocarbon product produced is greater than 65 weightpercent, preferably greater than 70 weight percent, more preferablygreater than 75 weight percent, and most preferably greater than 78weight percent.

In another embodiment of the process for conversion of one or moreoxygenates to one or more olefin(s), the amount ethylene produced inweight percent based on the total weight of hydrocarbon productproduced, is greater than 30 weight percent, more preferably greaterthan 35 weight percent, and most preferably greater than 40 weightpercent. In yet another embodiment of the process for conversion of oneor more oxygenates to one or more olefin(s), the amount of propyleneproduced in weight percent based on the total weight of hydrocarbonproduct produced is greater than 20 weight percent, preferably greaterthan 25 weight percent, more preferably greater than 30 weight percent,and most preferably greater than 35 weight percent.

The feedstock, in one embodiment, contains one or more diluent(s),typically used to reduce the concentration of the feedstock, and aregenerally non-reactive to the feedstock or molecular sieve catalystcomposition. Non-limiting examples of diluents include helium, argon,nitrogen, carbon monoxide, carbon dioxide, water, essentiallynon-reactive paraffins (especially alkanes such as methane, ethane, andpropane), essentially non-reactive aromatic compounds, and mixturesthereof. The most preferred diluents are water and nitrogen, with waterbeing particularly preferred.

The diluent, water, is used either in a liquid or a vapor form, or acombination thereof. The diluent is either added directly to a feedstockentering into a reactor or added directly into a reactor, or added witha molecular sieve catalyst composition. In one embodiment, the amount ofdiluent in the feedstock is in the range of from about 1 to about 99mole percent based on the total number of moles of the feedstock anddiluent, preferably from about 1 to 80 mole percent, more preferablyfrom about 5 to about 50, and most preferably from about 5 to about 25.

In one embodiment, other hydrocarbons are added to a feedstock eitherdirectly or indirectly, and include olefin(s), paraffin(s), aromatic(s)(see for example U.S. Pat. No. 4,677,242, addition of aromatics) ormixtures thereof, preferably propylene, butylene, pentylene, and otherhydrocarbons having 4 or more carbon atoms, or mixtures thereof.

The process for converting a feedstock, especially a feedstockcontaining one or more oxygenates, in the presence of a molecular sievecatalyst composition of the invention, is carried out in a reactionprocess in a reactor, where the process is a fixed bed process, afluidized bed process (includes a turbulent bed process), preferably acontinuous fluidized bed process, and most preferably a continuous highvelocity fluidized bed process.

The reaction processes can take place in a variety of catalytic reactorssuch as hybrid reactors that have a dense bed or fixed bed reactionzones and/or fast fluidized bed reaction zones coupled together,circulating fluidized bed reactors, riser reactors, and the like.Suitable conventional reactor types are described in for example U.S.Pat. No. 4,076,796, U.S. Pat. No. 6,287,522 (dual riser), andFluidization Engineering, D. Kunii and O. Levenspiel, Robert E. KriegerPublishing Company, New York, N.Y. 1977, which are all herein fullyincorporated by reference. The preferred reactor type are riser reactorsgenerally described in Riser Reactor, Fluidization and Fluid-ParticleSystems, pages 48 to 59, F. A. Zenz and D. F. Othmer, ReinholdPublishing Corporation, New York, 1960, and U.S. Pat. No. 6,166,282(fast-fluidized bed reactor), and U.S. patent application Ser. No.09/564,613 filed May 4, 2000 (multiple riser reactor), which are allherein fully incorporated by reference.

In the preferred embodiment, a fluidized bed process or high velocityfluidized bed process includes a reactor system, a regeneration systemand a recovery system.

The reactor system preferably is a fluid bed reactor system having afirst reaction zone within one or more riser reactor(s) and a secondreaction zone within at least one disengaging vessel, preferablycomprising one or more cyclones. In one embodiment, the one or moreriser reactor(s) and disengaging vessel is contained within a singlereactor vessel. Fresh feedstock, preferably containing one or moreoxygenates, optionally with one or more diluent(s), is fed to the one ormore riser reactor(s) in which a molecular sieve catalyst composition orcoked version thereof is introduced. In one embodiment, the molecularsieve catalyst composition or coked version thereof is contacted with aliquid or gas, or combination thereof, prior to being introduced to theriser reactor(s), preferably the liquid is water or methanol, and thegas is an inert gas such as nitrogen.

In an embodiment, the amount of fresh liquid fed separately or jointlywith a vapor feedstock, to a reactor system is in the range of from 0.1weight percent to about 85 weight percent, preferably from about 1weight percent to about 75 weight percent, more preferably from about 5weight percent to about 65 weight percent based on the total weight ofthe feedstock including any diluent contained therein. The liquid andvapor feedstocks are preferably the same composition, or contain varyingproportions of the same or different feedstock with the same ordifferent diluent.

The feedstock entering the reactor system is preferably converted,partially or fully, in the first reactor zone into a gaseous effluentthat enters the disengaging vessel along with a coked molecular sievecatalyst composition. In the preferred embodiment, cyclone(s) within thedisengaging vessel are designed to separate the molecular sieve catalystcomposition, preferably a coked molecular sieve catalyst composition,from the gaseous effluent containing one or more olefin(s) within thedisengaging zone. Cyclones are preferred, however, gravity effectswithin the disengaging vessel will also separate the catalystcompositions from the gaseous effluent. Other methods for separating thecatalyst compositions from the gaseous effluent include the use ofplates, caps, elbows, and the like.

In one embodiment of the disengaging system, the disengaging systemincludes a disengaging vessel, typically a lower portion of thedisengaging vessel is a stripping zone. In the stripping zone the cokedmolecular sieve catalyst composition is contacted with a gas, preferablyone or a combination of steam, methane, carbon dioxide, carbon monoxide,hydrogen, or an inert gas such as argon, preferably steam, to recoveradsorbed hydrocarbons from the coked molecular sieve catalystcomposition that is then introduced to the regeneration system. Inanother embodiment, the stripping zone is in a separate vessel from thedisengaging vessel and the gas is passed at a gas hourly superficialvelocity (GHSV) of from 1 hr⁻¹ to about 20,000 hr⁻¹ based on the volumeof gas to volume of coked molecular sieve catalyst composition,preferably at an elevated temperature from 250° C. to about 750° C.,preferably from about 350° C. to 650° C., over the coked molecular sievecatalyst composition.

The conversion temperature employed in the conversion process,specifically within the reactor system, is in the range of from about200° C. to about 1000° C., preferably from about 250° C. to about 800°C., more preferably from about 250° C. to about 750° C., yet morepreferably from about 300° C. to about 650° C., yet even more preferablyfrom about 350° C. to about 600° C. most preferably from about 350° C.to about 550° C.

The conversion pressure employed in the conversion process, specificallywithin the reactor system, varies over a wide range including autogenouspressure. The conversion pressure is based on the partial pressure ofthe feedstock exclusive of any diluent therein. Typically the conversionpressure employed in the process is in the range of from about 0.1 kpaato about 5 MPaa, preferably from about 5 kpaa to about 1 MPaa, and mostpreferably from about 20 kpaa to about 500 kPaa.

The weight hourly space velocity (WHSV), particularly in a process forconverting a feedstock containing one or more oxygenates in the presenceof a molecular sieve catalyst composition within a reaction zone, isdefined as the total weight of the feedstock excluding any diluents tothe reaction zone per hour per weight of molecular sieve in themolecular sieve catalyst composition in the reaction zone. The WHSV ismaintained at a level sufficient to keep the catalyst composition in afluidized state within a reactor.

Typically, the WHSV ranges from about 1 hr⁻¹ to about 5000 hr⁻¹,preferably from about 2 hr⁻¹ to about 3000 hr⁻¹, more preferably fromabout 5 hr⁻¹ to about 1500 hr⁻¹, and most preferably from about 10 hr⁻¹to about 1000 hr⁻¹. In one preferred embodiment, the WHSV is greaterthan 20 hr⁻¹, preferably the WHSV for conversion of a feedstockcontaining methanol and dimethyl ether is in the range of from about 20hr⁻¹ to about 300 hr⁻¹.

The superficial gas velocity (SGV) of the feedstock including diluentand reaction products within the reactor system is preferably sufficientto fluidize the molecular sieve catalyst composition within a reactionzone in the reactor. The SGV in the process, particularly within thereactor system, more particularly within the riser reactor(s), is atleast 0.1 meter per second (m/sec), preferably greater than 0.5 m/sec,more preferably greater than 1 m/sec, even more preferably greater than2 m/sec, yet even more preferably greater than 3 m/sec, and mostpreferably greater than 4 m/sec. See for example U.S. patent applicationSer. No. 09/708,753 filed Nov. 8, 2000, which is herein incorporated byreference.

In one preferred embodiment of the process for converting an oxygenateto olefin(s) using a silicoaluminophosphate molecular sieve catalystcomposition, the process is operated at a WHSV of at least 20 hr⁻¹ and aTemperature Corrected Normalized Methane Selectivity (TCNMS) of lessthan 0.016, preferably less than or equal to 0.01. See for example U.S.Pat. No. 5,952,538, which is herein fully incorporated by reference. Inanother embodiment of the processes for converting an oxygenate such asmethanol to one or more olefin(s) using a molecular sieve catalystcomposition, the WHSV is from 0.01 hr⁻¹ to about 100 hr⁻¹, at atemperature of from about 350° C. to 550° C., and silica to Me₂O₃ (Me isa Group IIIA or VIII element from the Periodic Table of Elements) molarratio of from 300 to 2500. See for example EP-0 642 485 B1, which isherein fully incorporated by reference. Other processes for convertingan oxygenate such as methanol to one or more olefin(s) using a molecularsieve. catalyst composition are described in PCT WO 01/23500 publishedApr. 5, 2001 (propane reduction at an average catalyst feedstockexposure of at least 1.0), which is herein incorporated by reference.

The coked molecular sieve catalyst composition is withdrawn from thedisengaging vessel, preferably by one or more cyclones(s), andintroduced to the regeneration system. The regeneration system comprisesa regenerator where the coked catalyst composition is contacted with aregeneration medium, preferably a gas containing oxygen, under generalregeneration conditions of temperature, pressure and residence time.Non-limiting examples of the regeneration medium include one or more ofoxygen, O₃, SO₃, N₂O, NO, NO₂, N₂O₅, air, air diluted with nitrogen orcarbon dioxide, oxygen and water (U.S Pat. No. 6,245,703), carbonmonoxide and/or hydrogen. The regeneration conditions are those capableof burning coke from the coked catalyst composition, preferably to alevel less than 0.5 weight percent based on the total weight of thecoked molecular sieve catalyst composition entering the regenerationsystem. The coked molecular sieve catalyst composition withdrawn fromthe regenerator forms a regenerated molecular sieve catalystcomposition.

The regeneration temperature is in the range of from about 200° C. toabout 1500° C., preferably from about 300° C. to about 1000° C., morepreferably from about 450° C. to about 750° C., and most preferably fromabout 550° C. to 700° C. The regeneration pressure is in the range offrom about 15 psia (103 kPaa) to about 500 psia (3448 kpaa), preferablyfrom about 20 psia (138 kpaa) to about 250 psia (1724 kpaa), morepreferably from about 25 psia (172 kPaa) to about 150 psia (1034 kpaa),and most preferably from about 30 psia (207 kPaa) to about 60 psia (414kpaa). The preferred residence time of the molecular sieve catalystcomposition in the regenerator is in the range of from about one minuteto several hours, most preferably about one minute to 100 minutes, andthe preferred volume of oxygen in the gas is in the range of from about0.01 mole percent to about 5 mole percent based on the total volume ofthe gas.

In one embodiment, regeneration promoters, typically metal containingcompounds such as platinum, palladium and the like, are added to theregenerator directly, or indirectly, for example with the coked catalystcomposition. Also, in another embodiment, a fresh molecular sievecatalyst composition is added to the regenerator containing aregeneration medium of oxygen and water as described in U.S. Pat. No.6,245,703, which is herein fully incorporated by reference. In yetanother embodiment, a portion of the coked molecular sieve catalystcomposition from the regenerator is returned directly to the one or moreriser reactor(s), or indirectly, by pre-contacting with the feedstock,or contacting with fresh molecular sieve catalyst composition, orcontacting with a regenerated molecular sieve catalyst composition or acooled regenerated molecular sieve catalyst composition described below.

The burning of coke is an exothermic reaction, and in an embodiment, thetemperature within the regeneration system is controlled by varioustechniques in the art including feeding a cooled gas to the regeneratorvessel, operated either in a batch, continuous, or semi-continuous mode,or a combination thereof. A preferred technique involves withdrawing theregenerated molecular sieve catalyst composition from the regenerationsystem and passing the regenerated molecular sieve catalyst compositionthrough a catalyst cooler that forms a cooled regenerated molecularsieve catalyst composition. The catalyst cooler, in an embodiment, is aheat exchanger that is located either internal or external to theregeneration system. In one embodiment, the cooler regenerated molecularsieve catalyst composition is returned to the regenerator in acontinuous cycle, alternatively, (see U.S. patent application Ser. No.09/587,766 filed Jun. 6, 2000) a portion of the cooled regeneratedmolecular sieve catalyst composition is returned to the regeneratorvessel in a continuous cycle, and another portion of the cooledmolecular sieve regenerated molecular sieve catalyst composition isreturned to the riser reactor(s), directly or indirectly, or a portionof the regenerated molecular sieve catalyst composition or cooledregenerated molecular sieve catalyst composition is contacted withby-products within the gaseous effluent (PCT WO 00/49106 published Aug.24, 2000), which are all herein fully incorporated by reference. Inanother embodiment, a regenerated molecular sieve catalyst compositioncontacted with an alcohol, preferably ethanol, 1-propnaol, 1-butanol ormixture thereof, is introduced to the reactor system, as described inU.S. patent application Ser. No. 09/785,122 filed Feb. 16, 2001, whichis herein fully incorporated by reference. Other methods for operating aregeneration system are in disclosed U.S. Pat. No. 6,290,916(controlling moisture), which is herein fully incorporated by reference.

The regenerated molecular sieve catalyst composition withdrawn from theregeneration system, preferably from the catalyst cooler, is combinedwith a fresh molecular sieve catalyst composition and/or re-circulatedmolecular sieve catalyst composition and/or feedstock and/or fresh gasor liquids, and returned to the riser reactor(s). In another embodiment,the regenerated molecular sieve catalyst composition withdrawn from theregeneration system is returned to the riser reactor(s) directly,preferably after passing through a catalyst cooler. In one embodiment, acarrier, such as an inert gas, feedstock vapor, steam or the like,semi-continuously or continuously, facilitates the introduction of theregenerated molecular sieve catalyst composition to the reactor system,preferably to the one or more riser reactor(s).

By controlling the flow of the regenerated molecular sieve catalystcomposition or cooled regenerated molecular sieve catalyst compositionfrom the regeneration system to the reactor system, the optimum level ofcoke on the molecular sieve catalyst composition entering the reactor ismaintained. There are many techniques for controlling the flow of amolecular sieve catalyst composition described in Michael Louge,Experimental Techniques, Circulating Fluidized Beds, Grace, Avidan andKnowlton, eds., Blackie, 1997 (336-337), which is herein incorporated byreference. Coke levels on the molecular sieve catalyst composition ismeasured by withdrawing from the conversion process the molecular sievecatalyst composition at a point in the process and determining itscarbon content. Typical levels of coke on the molecular sieve catalystcomposition, after regeneration is in the range of from 0.01 weightpercent to about 15 weight percent, preferably from about 0.1 weightpercent to about 10 weight percent, more preferably from about 0.2weight percent to about 5 weight percent, and most preferably from about0.3 weight percent to about 2 weight percent based on the total weightof the molecular sieve and not the total weight of the molecular sievecatalyst composition.

In one preferred embodiment, the mixture of fresh molecular sievecatalyst composition and regenerated molecular sieve catalystcomposition and/or cooled regenerated molecular sieve catalystcomposition contains in the range of from about 1 to 50 weight percent,preferably from about 2 to 30 weight percent, more preferably from about2 to about 20 weight percent, and most preferably from about 2 to about10 coke or carbonaceous deposit based on the total weight of the mixtureof molecular sieve catalyst compositions. See for example U.S. Pat. No.6,023,005, which is herein fully incorporated by reference.

The gaseous effluent is withdrawn from the disengaging system and ispassed through a recovery system. There are many well known recoverysystems, techniques and sequences that are useful in separatingolefin(s) and purifying olefin(s) from the gaseous effluent. Recoverysystems generally comprise one or more or a combination of a variousseparation, fractionation and/or distillation towers, columns,splitters, or trains, reaction systems such as ethylbenzene manufacture(U.S. Pat. No. 5,476,978) and other derivative processes such asaldehydes, ketones and ester manufacture (U.S. Pat. No. 5,675,041), andother associated equipment for example various condensers, heatexchangers, refrigeration systems or chill trains, compressors,knock-out drums or pots, pumps, and the like. Non-limiting examples ofthese towers, columns, splitters or trains used alone or in combinationinclude one or more of a demethanizer, preferably a high temperaturedemethanizer, a dethanizer, a depropanizer, preferably a wetdepropanizer, a wash tower often referred to as a caustic wash towerand/or quench tower, absorbers, adsorbers, membranes, ethylene (C2)splitter, propylene (C3) splitter, butene (C4) splitter, and the like.

Various recovery systems useful for recovering predominately olefin(s),preferably prime or light olefin(s) such as ethylene, propylene and/orbutene are described in U.S. Pat. No. 5,960,643 (secondary rich ethylenestream), U.S. Pat. Nos. 5,019,143, 5,452,581 and 5,082,481 (membraneseparations), U.S. Pat. No. 5,672,197 (pressure dependent adsorbents),U.S. Pat. No. 6,069,288 (hydrogen removal), U.S. Pat. No. 5,904,880(recovered methanol to hydrogen and carbon dioxide in one step), U.S.Pat. No. 5,927,063 (recovered methanol to gas turbine power plant), andU.S. Pat. No. 6,121,504 (direct product quench), U.S. Pat. No. 6,121,503(high purity olefins without superfractionation), and U.S. Pat. No.6,293,998 (pressure swing adsorption), which are all herein fullyincorporated by reference.

Generally accompanying most recovery systems is the production,generation or accumulation of additional products, by-products and/orcontaminants along with the preferred prime products. The preferredprime products, the light olefins, such as ethylene and propylene, aretypically purified for use in derivative manufacturing processes such aspolymerization processes. Therefore, in the most preferred embodiment ofthe recovery system, the recovery system also includes a purificationsystem. For example, the light olefin(s) produced particularly in a MTOprocess are passed through a purification system that removes low levelsof by-products or contaminants. Non-limiting examples of contaminantsand by-products include generally polar compounds such as water,alcohols, carboxylic acids, ethers, carbon oxides, sulfur compounds suchas hydrogen sulfide, carbonyl sulfides and mercaptans, ammonia and othernitrogen compounds, arsine, phosphine and chlorides. Other contaminantsor by-products include hydrogen and hydrocarbons such as acetylene,methyl acetylene, propadiene, butadiene and butyne.

Other recovery systems that include purification systems, for examplefor the purification of olefin(s), are described in Kirk-OthmerEncyclopedia of Chemical Technology, 4th Edition, Volume 9, John Wiley &Sons, 1996, pages 249-271 and 894-899, which is herein incorporated byreference. Purification systems are also described in for example, U.S.Pat. No. 6,271,428 (purification of a diolefin hydrocarbon stream), U.S.Pat. No. 6,293,999 (separating propylene from propane), and U.S. patentapplication Ser. No. 09/689,363 filed Oct. 20, 2000 (purge stream usinghydrating catalyst), which is herein incorporated by reference.

Typically, in converting one or more oxygenates to olefin(s) having 2 or3 carbon atoms, an amount of hydrocarbons, particularly olefin(s),especially olefin(s) having 4 or more carbon atoms, and otherby-products are formed or produced. Included in the recovery systems ofthe invention are reaction systems for converting the products containedwithin the effluent gas withdrawn from the reactor or converting thoseproducts produced as a result of the recovery system utilized.

In one embodiment, the effluent gas withdrawn from the reactor is passedthrough a recovery system producing one or more hydrocarbon containingstream(s), in particular, a three or more carbon atom (C₃ ⁺) hydrocarboncontaining stream. In this embodiment, the C₃ ⁺ hydrocarbon containingstream is passed through a first fractionation zone producing a crude C₃hydrocarbon and a C₄ ⁺ hydrocarbon containing stream, the C₄ ⁺hydrocarbon containing stream is passed through a second fractionationzone producing a crude C₄ hydrocarbon and a C₅ ⁺ hydrocarbon containingstream. The four or more carbon hydrocarbons include butenes such asbutene-1 and butene-2, butadienes, saturated butanes, and isobutanes.

The effluent gas removed from a conversion process, particularly a MTOprocess, typically has a minor amount of hydrocarbons having 4 or morecarbon atoms. The amount of hydrocarbons having 4 or more carbon atomsis typically in an amount less than 20 weight percent, preferably lessthan 10 weight percent, more preferably less than 5 weight percent, andmost preferably less than 2 weight percent, based on the total weight ofthe effluent gas withdrawn from a MTO process, excluding water. Inparticular with a conversion process of oxygenates into olefin(s)utilizing a molecular sieve catalyst composition the resulting effluentgas typically comprises a majority of ethylene and/or propylene and aminor amount of four carbon and higher carbon number products and otherby-products, excluding water.

Suitable well known reaction systems as part of the recovery systemprimarily take lower value products and convert them to higher valueproducts. For example, the C₄ hydrocarbons, butene-1 and butene-2 areused to make alcohols having 8 to 13 carbon atoms, and other specialtychemicals, isobutylene is used to make a gasoline additive,methyl-t-butylether, butadiene in a selective hydrogenation unit isconverted into butene-1 and butene-2, and butane is useful as a fuel.Non-limiting examples of reaction systems include U.S. Pat. No.5,955,640 (converting a four carbon product into butene-1), U.S. Pat.No. 4,774,375 (isobutane and butene-2 oligomerized to an alkylategasoline), U.S. Pat. No. 6,049,017 (dimerization of n-butylene), U.S.Pat. Nos. 4,287,369 and 5,763,678 (carbonylation or hydroformulation ofhigher olefins with carbon dioxide and hydrogen making carbonylcompounds), U.S. Pat. No. 4,542,252 (multistage adiabatic process), U.S.Pat. No. 5,634,354 (olefin-hydrogen recovery), and Cosyns, J. et al.,Process for Upgrading C3, C ₄ and C ₅ Olefinic Streams, Pet. & Coal,Vol. 37, No. 4 (1995) (dimerizing or oligomerizing propylene, butyleneand pentylene), which are all herein fully incorporated by reference.

The preferred light olefin(s) produced by any one of the processesdescribed above, preferably conversion processes, are high purity primeolefin(s) products that contains a single carbon number olefin in anamount greater than 80 percent, preferably greater than 90 weightpercent, more preferably greater than 95 weight percent, and mostpreferably no less than about 99 weight percent, based on the totalweight of the olefin.

In one embodiment, high purity prime olefin(s) are produced in theprocess of the invention at rate of greater than 5 kg per day,preferably greater than 10 kg per day, more preferably greater than 20kg per day, and most preferably greater than 50 kg per day. In anotherembodiment, high purity ethylene and/or high purity propylene isproduced by the process of the invention at a rate greater than 4,500 kgper day, preferably greater than 100,000 kg per day, more preferablygreater than 500,000 kg per day, even more preferably greater than1,000,000 kg per day, yet even more preferably greater than 1,500,000 kgper day, still even more preferably greater than 2,000,000 kg per day,and most preferably greater than 2,500,000 kg per day.

In another embodiment, the feedstock is fed to a reactor in an amount ofgreater than 16 Kg per hour, preferably greater than 32 Kg per hour,more preferably greater than 160 Kg per hour, even more preferablygreater than 14,400 Kg per hour, and most preferably greater than8,000,000 Kg per hour.

In one embodiment, the feedstock, preferably a feedstock comprising anoxygenate, more preferably a feedstock comprising methanol is fed to areactor, preferably a reactor containing molecular sieve catalyst, asthe conductivity level is monitored. The conductivity level is monitoredto be within the desired conductivity limits so as not to adverselyimpact the molecular sieve catalyst. In particular, the conductivitylevel should either enhance selectivity of feedstock conversion toethylene and propylene or have no significant effect on the selectivity.In addition, the conductivity level should not be so high as tosignificantly affect catalyst life.

In this invention, the feedstock can also be monitored for concentrationof Group IA or IIA metals. The concentration levels of these metalscorrelate well with the desired conductivity levels, and more accuratelyreflect contamination levels in general. In one embodiment, thefeedstock comprises methanol and/or dimethyl ether, and furthercomprises less than 50 wppm, preferably less than 40 wppm, morepreferably less than 30 wppm, even more preferably less than 20 wppm,yet even more preferably less than 10 wppm, and most preferably lessthan 1 wppm of a Group IA metal salt and/or a Group IIA metal salt,preferably a Group IA metal salt such as sodium chloride and/orpotassium chloride, based on total weight of the feedstock.

In another embodiment, the feedstock comprises at least 25 wppb of aGroup IA metal salt and/or a Group IIA metal salt. More preferably thefeedstock comprises at least 50 wppb, even more preferably at least 100wppb, yet even more preferably at least 150 wppb, still even morepreferably at least 250 wppb, and most preferably at least 500 wppb of aGroup IA metal salt and/or a Group IIA, metal salt, based on totalweight of the feedstock.

In still another embodiment, the feedstock, preferably a feedstockcomprising an oxygenate, more preferably a feedstock comprising methanoland/or dimethyl ether, further comprises in the range of from 10 wppb toabout 50 wppm, preferably in the range of from about 10 wppb to about 40wppm, more preferably in the range of from 15 wppb to about 30 wppm,even more preferably in the range of from 15 wppb to about 20 wppm, yeteven more preferably in the range of from 10 wppb to about 10 wppm of aGroup IA metal salt and/or a Group IIA metal salt, preferably a Group IAmetal salt such as sodium chloride and/or potassium chloride, based ontotal weight of the feedstock.

In another embodiment, a feedstock is provided which has a substantiallyhigh concentration of a Group IA and/or Group IIA metal salt. An amountof the metal salt is removed from the feedstock to form a treatedfeedstock. The treated feedstock is provided to a reactor and contactedwith molecular sieve to form an olefin product. In a particularembodiment, the amount of a Group IA and/or Group IIA metal salt in thefeedstock is less than 10,000 wppm of a Group IA and/or Group IIA metalsalt such as sodium chloride and/or potassium chloride, more preferablyless than 5,000 wppm, even more preferably less than

wppm, yet even more preferably less than 500 wppm, still even morepreferably less than 250 wppm, and most preferably less than 100 wppm,based on total weight of the feedstock. This feedstock is then treatedto reduce conductivity and contacted with molecular sieve to form olefinproduct.

In another embodiment, the feedstock which contains a substantially highconcentration of a Group IA and/or Group IIA metal salt has aconductivity of not greater than about 750 uS/cm. Preferably, thefeedstock which contains a substantially high concentration of a GroupIA and/or Group IIA metal salt has a conductivity of not greater thanabout 500 uS/cm, more preferably not greater than about 300 uS/cm. Theconductivity of the feedstock which contains the substantially highconcentration of a Group IA and/or Group IIA metal salt is then reducedto more the more desirable conductivity levels prior to contact withmolecular sieve catalyst.

In another embodiment, the feedstock, preferably an oxygenate, morepreferably methanol and/or dimethylether is substantially free of aGroup IA metal salt and/or a Group IIA metal salt, preferably a Group IAmetal salt, and most preferably sodium chloride and/or potassiumchloride. For the purposes of this patent specification and appendedclaims the term “substantially free” means that the feedstock comprisesless than 30 ppm, preferably less than 29.4 ppm of a Group IA metal saltand/or a Group IIA metal salt, most preferably sodium chloride andpotassium chloride or ions thereof.

Conventional well known chemical analysis techniques, such as AtomicAdsorption Spectroscopy (AAS), can be used to measure the amount ofsalts in the methanol feedstock. Introduction to Zeolite Science andPractice, H. van Bekkum, E. M. Flanigan, J. C. Janssen (editors),Elsevier, 1991, p. 259.

Other conversion processes, in particular, a conversion process of anoxygenate to one or more olefin(s) in the presence of a molecular sievecatalyst composition, especially where the molecular sieve issynthesized from a silicon-, phosphorous-, and alumina-source, includethose described in for example: U.S. Pat. No. 6,121,503 (making plasticwith an olefin product having a paraffin to olefin weight ratio lessthan or equal to 0.05), U.S. Pat. No. 6,187,983 (electromagnetic energyto reaction system), PCT WO 99/18055 publishes Apr. 15, 1999 (heavyhydrocarbon in effluent gas fed to another reactor) PCT WO 01/60770published Aug. 23, 2001 and U.S. patent application Ser. No. 09/627,634filed Jul. 28, 2000 (high pressure), U.S. patent application Ser. No.09/507,838 filed Feb. 22, 2000 (staged feedstock injection), and U.S.patent application Ser. No. 09/785,409 filed Feb. 16, 2001 (acetoneco-fed), which are all herein fully incorporated by reference.

In an embodiment, an integrated process is directed to producing lightolefin(s) from a hydrocarbon feedstock, preferably a hydrocarbon gasfeedstock, more preferably methane and/or ethane. The first step in theprocess is passing the gaseous feedstock, preferably in combination witha water stream, to a syngas production zone to produce a synthesis gas(syngas) stream. Syngas production is well known, and typical syngastemperatures are in the range of from about 700° C. to about 1200° C.and syngas pressures are in the range of from about 2 MPa to about 100MPa. Synthesis gas streams are produced from natural gas, petroleumliquids, and carbonaceous materials such as coal, recycled plastic,municipal waste or any other organic material, preferably synthesis gasstream is produced via steam reforming of natural gas. Generally, aheterogeneous catalyst, typically a copper based catalyst, is contactedwith a synthesis gas stream, typically carbon dioxide and carbonmonoxide and hydrogen to produce an alcohol, preferably methanol, oftenin combination with water. In one embodiment, the synthesis gas streamat a synthesis temperature in the range of from about 150° C. to about450° C. and at a synthesis pressure in the range of from about 5 MPa toabout 10 MPa is passed through a carbon oxide conversion zone to producean oxygenate containing stream.

This oxygenate containing stream, or crude methanol, typically containsthe alcohol product and various other components such as ethers,particularly dimethyl ether, ketones, aldehydes, dissolved gases such ashydrogen methane, carbon oxide and nitrogen, and fusel oil. Theoxygenate containing stream, crude methanol, in the preferred embodimentis passed through a well known purification processes, distillation,separation and fractionation, resulting in a purified oxygenatecontaining stream, for example, commercial Grade A and AA methanol. Theoxygenate containing stream or purified oxygenate containing stream,optionally with one or more diluents, is contacted with one or moremolecular sieve catalyst composition described above in any one of theprocesses described above to produce a variety of prime products,particularly light olefin(s), ethylene and/or propylene. Non-limitingexamples of this integrated process is described in EP-B-0 933 345,which is herein fully incorporated by reference. In another more fullyintegrated process, optionally with the integrated processes describedabove, olefin(s) produced are directed to, in one embodiment, one ormore polymerization processes for producing various polyolefins. (Seefor example U.S. patent application Ser. No. 09/615,376 filed Jul. 13,2000, which is herein fully incorporated by reference.)

Polymerization processes include solution, gas phase, slurry phase and ahigh pressure processes, or a combination thereof. Particularlypreferred is a gas phase or a slurry phase polymerization of one or moreolefin(s) at least one of which is ethylene or propylene. Thesepolymerization processes utilize a polymerization catalyst that caninclude any one or a combination of the molecular sieve catalystsdiscussed above, however, the preferred polymerization catalysts arethose Ziegler-Natta, Phillips-type, metallocene, metallocene-type andadvanced polymerization catalysts, and mixtures thereof. The polymersproduced by the polymerization processes described above include linearlow density polyethylene, elastomers, plastomers, high densitypolyethylene, low density polyethylene, polypropylene and polypropylenecopolymers. The propylene based polymers produced by the polymerizationprocesses include atactic polypropylene, isotactic polypropylene,syndiotactic polypropylene, and propylene random, block or impactcopolymers.

In preferred embodiment, the integrated process comprises a polymerizingprocess of one or more olefin(s) in the presence of a polymerizationcatalyst system in a polymerization reactor to produce one or morepolymer products, wherein the one or more olefin(s) having been made byconverting an alcohol, particularly methanol, using a molecular sievecatalyst composition. The preferred polymerization process is a gasphase polymerization process and at least one of the olefins(s) iseither ethylene or propylene, and preferably the polymerization catalystsystem is a supported metallocene catalyst system. In this embodiment,the supported metallocene catalyst system comprises a support, ametallocene or metallocene-type compound and an activator, preferablythe activator is a non-coordinating anion or alumoxane, or combinationthereof, and most preferably the activator is alumoxane.

In addition to polyolefins, numerous other olefin derived products areformed from the olefin(s) recovered any one of the processes describedabove, particularly the conversion processes, more particularly the GTOprocess or MTO process. These include, but are not limited to,aldehydes, alcohols, acetic acid, linear alpha olefins, vinyl acetate,ethylene dicholoride and vinyl chloride, ethylbenzene, ethylene oxide,cumene, isopropyl alcohol, acrolein, allyl chloride, propylene oxide,acrylic acid, ethylene-propylene rubbers, and acrylonitrile, and trimersand dimers of ethylene, propylene or butylenes.

VI. EXAMPLES

In order to provide a better understanding of the present inventionincluding representative advantages thereof, the following examples areoffered.

Example 1

By physical mixing sodium chloride (NaCl) or potassium chloride (KCl)with a SAPO-34 molecular sieve synthesized in accordance with well knownprocedures, (many of these procedures are discussed in this patentspecification and are herein fully incorporated by reference) theSAPO-34 molecular sieve having a salt loading of 7.5 wt % was obtained.After mixing the salts and the molecular sieve, the combination wascalcined for 5 hrs in N₂ followed by three hours in air at 650° C. Anexamination of the structural integrity of these mixtures was measuredusing well known X-ray diffraction techniques. In examining the XRDpatterns of the untreated SAPO-34 molecular sieve versus the salttreated sieves, a clear reduction in XRD crystallinity was seen with thesalt treated molecular sieves. In addition, the XRD pattern of the salttreated sieves showed a new peak, which is indicative of the formationof a new, unknown phase.

Examples 2 through 9

In these Examples 2 though 9, the same SAPO-34 molecular sieve used inExample 1 were mixed, separately, with salt solutions in methanol of thefollowing salts: NaCl, MgCl₂ or KNO₃. The salt loadings on the molecularsieve ranged from about 80 to about 10,000 weight ppm. After mixing, themethanol was evaporated at temperatures between about 90° C. and about120° C., and the formed dry solid was subsequently calcined for 5 hrs inN₂ followed by 3 hours in air at 650° C. The performance of thesemolecular sieve/salt mixtures were evaluated in a fixed bed reactor at450° C., 25 WHSV and 25 psig (172 kpag). The reaction product wasanalyzed by on-line GC. Weight average light olefin selectivity(ethylene and propylene) were determined as well as catalyst life(measured in terms of grams of methanol converted per grams of molecularsieve). The results are summarized in Table 1 below.

TABLE 1 -Cat. Life Selectivity (gm MeOH (wt % Concentration convertedper ethylene + Example Salt type (wppm on sieve) gm of sieve) propylene)Standard None 0 18.8 74.6 2 NaCl 84.0 16.7 75.0 3 NaCl 400.0 17.1 74.3 4NaCl 4000.0 15.9 73.5 5 NaCl 10000.0 11.9 72.0 6 NaNO₃ 84.0 17.4 74.6 7NaNO₃ 8400.0 16.1 72.4 8 MgCl₂ 84.0 18.1 74.1 9 MgCl₂ 8400.0 16.3 74.0From Table 1 the negative effect of salt on catalyst life and lightolefin selectivity demonstrated.

Example 10

This example illustrates the conversion of a Group IA and/or IIA metalsalt based on total molecular sieve content to a Group IA and/or IIAmetal salt in the oxygenate feedstock, for example in the methanol feed.Table 2 shows examples of NaCl concentrations in a methanol feed. Theseconcentrations correspond to the respective NaCl concentrations onmolecular sieve as shown above in Table 1. For the purposes of thisexample, the expected catalyst lifetime in a large scale MTO plant issix (6) months, and that a methanol feed pre-treatment step, forexample, the vaporization system of the MTO plant, is capable ofremoving 99.9 wt % of the NaCl in the methanol feed before the vaporizedmethanol contacts the molecular sieve catalyst composition. The weighthourly space velocity of the methanol feed is 25 hr⁻¹. It is alsounderstood that a lower percentage removal less than 99.9 wt % wouldresult in lower amount of a Group IA and/or IIA metal salt present inthe feed or in contact with the catalyst.

TABLE 2 NaCl Concentration NaCl concentration in methanol feed (weightppm on molecular sieve) (weight ppm) 0.0 0.0 84.0 0.6 400 2.9 4000 29.410000 73.1

Example 11

Seawater from off the coast of Stavienisse, a village located on thewestern point of the island of Tholen, the Netherlands, was collected at−21 meters. A sample of the seawater was mixed with pure methanol(Merck, p.a.), and conductivity was measured using a Schott GeraiteConductivity meter (Type CG857), equipped with a LF100 conductivityprobe. Samples of the mixed methanol and seawater were further dilutedwith methanol at various concentrations, and the conductivity measured.The results are shown in Table 3.

TABLE 3 Sample Sample Ave. Sample MeOH Seawater 1 3 Conc. Cond. # (gm.)(gm.) (gm.) (gm.) (wppm) (uS/cm) 1 34.6164 0.04146 1196 46.4 2 23.270218.0215 307 12.8 3 88.85 9.8400 119 7.8 4 22.027 5.6109 30 3.9 5 28.60912.5944 11 3.4

Example 12

Additional seawater samples from the seawater described in Example 11were diluted with methanol and the conductivity of the mixtures weremeasured. The results are shown in Table 4.

TABLE 4 Cond. Cond. Ave. Sample MeOH Seawater Conc. (1) (2) Cond. #(gm.) (gm.) (wppm) (uS/cm) (uS/cm) (uS/cm) 1 15.000 0.000 0 0.7 0.7 0.71 14.99 0 0 1.5 1.2 1.35 2 16.74942 0.00647 386 18.5 18.5 18.5 315.04122 0.02028 1346 54.8 54.5 54.65 4 14.64419 0.02196 1497 56.8 56.756.75 5 15.23638 0.02866 1877 66.3 66 66.15 6 15.45856 0.04632 2987102.9 102.7 102.8 2 13.330 0.063 4700 147.9 147.5 147.7 3 15.511 0.1217800 235 238 236.5 4 15.535 0.190 12,200 342 341 341.5 5 15.452 0.25016,200 439 443 441 6 15.103 0.317 21,000 542 534 538

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For example, it is contemplated thatthere are many ways of removing a salt from a feedstock comprising anoxygenate such as by boiling (i.e., distillation), methanol vapor/waterabsorbant absorber, and even ion exchange via a resin bed reactor usinga sulfonated polystyrene resin. For this reason, then, reference shouldbe made solely to the appended claims for purposes of determining thetrue scope of the present invention.

1. A process for converting oxygenate to olefin, comprising the stepsof: a) providing an oxygenate composition having a positive conductivityof not greater than 10 uS/cm and containing at least one Group IA orGroup IIA metal salt; b) contacting the oxygenate composition with amolecular sieve to convert oxygenate in the oxygenate composition toolefin; and c) converting the olefin to polyolefin.
 2. A process forconverting oxygenate to olefin, comprising the steps of: a) providing anoxygenate composition containing at least one Group IA or Group IIAmetal salt; b) reducing conductivity of the oxygenate composition toform a treated feedstock having a conductivity of not greater than 10uS/cm; c) contacting the treated feedstock with a molecular sieve toconvert oxygenate in the oxygenate composition to olefin, and d)converting the olefin to polyolefin.
 3. An integrated process for makingone or more olefin(s), the integrated process comprising the steps of:(a) passing a hydrocarbon feedstock to a syngas production zone toproducing a synthesis gas stream; (b) contacting the synthesis gasstream with a catalyst to form an oxygenated feedstock; (c) convertingthe oxygenated feedstock containing less than 50 ppm of a Group IA metalsalt and/or a Group IIA metal salt into the one or more olefin(s) in areactor in the presence of a molecular sieve catalyst composition; and(d) polymerizing the one or more olefin(s) in the presence of apolymerization catalyst into a polyolefin at a rate greater than 1,000Kg/hour wherein the hydrocarbon feedstock of step (a) comprises a gas.4. The process of claim 3, wherein the polymerization rate is greaterthan 10,000 Kg/hour.
 5. A process of converting an oxygenated feedstockinto one or more olefin(s) in the presence of a molecular sieve catalystcomposition comprising a molecular sieve, the process comprising thesteps of: (a) passing a hydrocarbon feedstock to a syngas productionzone producing a synthesis gas stream; (b) contacting the synthesis gasstream with a catalyst to form the oxygenated feedstock; (c)transporting the oxygenated feedstock containing a first amount of aGroup IA metal salt and/or a Group IIA metal salt; (d) removing from theoxygenated feedstock the Group IA metal salt and/or the Group IIA metalsalt such that feedstock contains a second amount of the Group IA and/orGroup IIA metal salt to form a treated oxygenated feedstock, wherein thesecond amount is less than the first amount; (e) converting the treatedoxygenated feedstock into the one or more olefin(s) in a reactor in thepresence of a molecular sieve catalyst composition; and (f) polymerizingthe one or more olefin(s) in the presence of a polymerization catalystinto a polyolefin at a rate greater than 1,000 Kg/hour, wherein thehydrocarbon feedstock of step (a) comprises a gas.